The invention relates to a steel container, especially intended for the storage and transport of bulk goods, the inner surfaces of the container being covered by walls made of corrosion-resistant material, which walls together form a closed box, the upright side walls and the top wall of which are substantially identical in shape to those of the steel container.
Such a container is disclosed in GB-A-1276795.
Transport of plastics particle material in steel ISO containers or steel high-cube containers produces problems if the plastics particles come into direct contact with the steel inner surfaces of the container walls. Steel particles which come loose as a result of corrosion of these walls are extremely damaging to the extruder in which the plastics particle material is processed, whilst, moreover, the product emerging from the extruder will be of relatively low quality. The customary solution to this problem is to hang up a large plastics sack (inner liner) in the container and to feed the plastics particles into this. This solution exhibits a number of drawbacks. The fitting of a sack in a container, the filling of the sack and the emptying thereof is time-consuming. Moreover the sacks are difficult to empty fully, so that material is left behind. In order to keep the sacks in place as the container is tipped, a frame (bulkhead) is erected, which can consist of wood and/or cardboard and/or steel tubular profiles. These materials have to be removed, which can cause a problem. Sometimes the sacks tear, so that steel particles emanating from the container manage, after all, to find their way into the plastics material. The sacks are used once and thrown away, including the plastics granules remaining therein, which is bad for the environment and entails costs.
The above-mentioned GB-A-1276795 deals with the difficulties encountered in forming the connection at the angular joint between two meeting walls especially at a corner where three walls meet. This problem is due to the fact that the walls seldom abut at exactly right angles. This document does not give a solution for the above-mentioned problems.
The object of the invention is to avoid the abovementioned problems with the transport of plastics particle material or other bulk material in containers, without experiencing the abovementioned drawbacks.
According to the invention, the steel container specified in the introduction is, to this end, characterized in that one or more fill openings are make either in a bulk head of the closed box or in the upper wall of the closed box, which fill openings may be closed off by a lid and can be brought in communication with the space outside the steel container via an open door or via an opening in the upper wall of the container, that one or more discharge openings are made either in a bulkhead of the closed box or in the lower wall of the closed box, which discharge openings can be closed off by a lid, and that the discharge openings are flanged by funnel-shaped bottom walls extending towards the discharge openings.
As the corrosion-resistant material, stainless steel and hard plastic (including composite) enter into consideration, though an aluminium alloy, for example an aluminium magnesium alloy, is preferable owing to the low price and low weight and the excellent anti-corrosive properties.
The transportation of solid plastics in the containers according to the invention, for example from the plastic producer to the processing plant, yields a positive environmental effect. The plastic remains pure. There is no loss of plastic. Both the steel walls of the container and the corrosion-resistant bin inside the container are recyclable.
In order to connect together the steel container walls and the walls of corrosion-resistant material, the fastening between the steel container walls and the walls of corrosion-resistant material can be formed by a bushing inserted through a mutually aligned opening in both walls and in which the screw bolt is turned, which bushing is deformed into an annular thickening lying against the outer side of the steel wall. Such a connection is denoted by the term blind rivet nut. At least the transitions from the long side walls into the top wall and from a short side wall into the top wall and the long side walls preferably comprise angled or rounded parts, which are welded at their bent-over flat ends to the vertical and horizontal walls of closed box
The internal bin of corrosion-resistant material must regularly be cleaned. This can easily be realized if a water pipe having spray openings emerging in the closed box of corrosion-resistant material is moulded onto those angled or rounded corner pieces of the box of corrosion-resistant material which run in the longitudinal direction of the container.
The invention further relates to a method for storing and transporting bulk material, especially plastics particle material, in containers, in which the bulk material is situated unpacked in the internal bin of a container according to one of the claims.